Bowstrings of compound bows have pulls in the order of 80 to 120 lbs (356-534 N). As an archery bowstring release is used by the archer, substantial forces are exerted on the release by the bowstring.
The use of wrist straps has become common to accommodate these large forces which have the potential to cause possible injury to the archer's fingers. A wrist strap spreads the force of the bow string over a relatively large surface area of the wrist and the back of the archer's hand while leaving at least the thumb or index finger of the hand free to activate or fire the trigger of the bowstring release.
Wrist straps have been closed onto and attached to the wrist of the user by buckles such as is disclosed in U.S. Pat. No. 5,261,463 to Ralph E. Harden, Sr., or hook and loop fasteners as disclosed in U.S. Pat. No. 4,831,997 to James H. Greene and U.S. Pat. No. 5,323,751 to Johnny Pittman et al. The hook and loop fasteners engage facing surfaces of the wrist strap ends and are overlaid one on the other and forcibly pressed together to engage the hooks and loops to provide the fastening function.
Buckles, while providing positive attachment, are awkward and generally only provide adjustments in fixed increments. The use of the buckle is more difficult than hook and loop fasteners because the typically right handed archer will be using the left hand to buckle the wrist strap about his wrist, a manual operation which a person would normally use two hands to accomplish if possible. Depending upon the spacing of the holes which the buckle keeper engages, the strap may be either too loose or too tight for comfort, and/or for reliability on the archer's wrist.
The incorporation of the hook and loop fasteners into a wrist strap provides increased comfort, ease of attachment, and infinite adjustment of the wrist strap size over a substantial range. The use of the hook and loop fasteners also tends to eliminate the need to manufacture and stock multiple sizes of the wrist strap and thus can accommodate a generally wider spectrum of wrist sizes.
However, a significant drawback in the use of the hook and loop fasteners to attach the two distal ends of the archery bowstring wrist strap is in the loading of the strap by pulling on the bowstring. The hooks of the wrist strap may not fully retain engagement with loops of the hook and loop fastener. This may be due to several reasons including partial straightening of the hooks from extended use, a failure to fully and properly engage the hooks and loops, or the placement of the hook and loop fasteners in an orientation whereby the force of the bowstring causes a peeling action and thus peels the fastener apart, releasing the strap.
Further, for those users having a large circumference wrist, the surface area of engagement of the hook and loop fastener may be reduced to the point that the hook and loop fasteners may become ineffective under load and release the strap.
If the wrist strap separates under load, the result either can be a misdirected shot which may or may not be of serious consequence or a possible injury to the archer by virtue of the fact that the bowstring will pull the wrist strap from the wrist and the strap and release will flail about as the bowstring stops its forward motion. Since the archer's other hand and arm are disposed in an area close to the path of bowstring movement, the wrist strap and/or the bowstring release may strike the archer's arm or other hand. An extremely high velocity and the force of an 80-120 lb pull bow could seriously injure the archer's hand or arm.